noun
Etymology: from gerund of resolve (I)
1. : the ability of an optical system to form distinguishable images of objects separated by small angular distances
2. : the ability of a photographic film or plate to reproduce the fine detail of an optical image commonly evaluated in lines per millimeter
3. : the ability of observing equipment to give evidence of the existence and nature of celestial objects of very small angular dimensions depending especially on the wavelength of the received radiation and being least for longest wavelengths